Experiment on mice highlights concern over genetic engineering

By
Robert C. Cowen, Natural science editor of The Christian Science Monitor /
December 20, 1982

By successfully implanting a rat gene in mice which then grew to abnormal size, six molecular biologists have dramatized the speed with which the new field of genetic engineering is developing.

They also have highlighted the timeliness of the concern - recently expressed in Congress, by a presidential commission, and by the National Council of Churches - that genetic engineering be brought under stronger social control.

The transplantation of a rat gene that carries the blueprint for a growth hormone is only the latest in a number of experiments to demonstrate that foreign genes can be implanted in higher organisms, including mice, and be made to work. These experiments are aimed primarily at learning how genes are controlled as they govern the development of an organism from embryo to adult. This is considered one of the leading unsolved puzzles in biology.

Thus, the main scientific interest in the new gene transplant technique lies more in the research opportunities it offers than in practical uses that may ultimately result. Reporting their work in Nature magazine, the scientists involved call it a ''powerful approach to the study of gene regulation and the genetic basis of development.''

Scientists from four institutions have collaborated in the research. They include Richard D. Palmiter of the University of Washington; Ralph I. Brinster, Robert Hammer, and Myrna Trumbauer of the University of Pennsylvania; Michael G. Rosenfield of the University of California at San Diego; and Neal C. Birnberg and Ronald M. Evans of the Salk Institute.

Their technique helps biologists over a major hurdle in studying how genes work in higher organisms. Experimenters have been able to implant genes. But they have been partly frustrated by lack of control over how genes behave once implanted. Often foreign genes simply do nothing at all.

Genes are sections of a molecule of DNA (deoxyribonucleic acid). They are controlled by information coded on other sections of the molecule. In this present case, the experimenters removed such a control sequence, called a promoter/regulator, from a normal mouse gene. They then spliced it onto a gene which has the code for a growth hormone in a rat.

This hybrid DNA section was implanted in fertilized mouse eggs which, in turn , were implanted in female mice. Many of the offspring then produced large amounts of the growth hormone. They grew to twice normal size. Moreover, at least one of them has passed the gene along to its own offspring.

This kind of thing has been done before. For example, Franklin Constantini and Elizabeth Lacy at Oxford University in England and Thomas Wagner and associates at Ohio University in the United States have successfully implanted a rabbit gene in mice. This is a gene coding for a form of the protein hemoglobin. It, too, appears to work in the mice and to be heritable. Now a new line of research has been opened by the mice experiment - research in which a strong and active regulating element can be fused to a gene before it is implanted.

In their paper on the mice experiment, the six researchers note that their technique could lead to such practical applications as accelerated growth rates of farm animals or increased yields of meat and milk. However, these must wait on a more thorough understanding of, and control over, the genetic engineering that would be involved.

Meanwhile concern for social implications of this developing technology has again been expressed in the report ''Splicing Life,'' which was released in November by the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research. This called genetic engineering ''probably one of the greatest technological revolutions in history.'' But it also warned of possible misuse in trying to redesign humans.

President Carter created the commission after prodding by the National Council of Churches, the Synagogue Council of America, and the United States Catholic Conference. These groups are concerned that this awesome technology is being developed with few controls. Research guidelines of the National Institutes of Health apply only to research NIH supports and address mainly questions of laboratory safety. The religious groups expressed alarm that no governmental body was ''exercising adequate oversight or control.'' The National Council of Churches reiterated this concern in a report of its own in November.

The presidential commission concluded that such concern is ''well founded.'' It hailed the new technology as ''a celebration of human creativity and freedom.'' It found no reason to advocate that work in the field be curtailed. But it urged creation of a suitable oversight body when ''human engineering'' might be involved.

This concern surfaced again in congressional hearings earlier this month. Most of some two dozen scientists, legal scholars, and ethicists who testified during a three-day session of the House subcommittee on investigations and oversight called for some form of overview agency. Rep. Albert Gore Jr. (D) of Tennessee, subcommittee chairman, plans to introduce a bill in the next Congress which would create such a body.